This invention relates generally to chucks having self-grasping, spreadable elements and more particularly to a quick detach bit for earth drilling operations.
In earth-type drilling apparatus, it is often required to replace a drill bit due to wear or breakage. Under ordinary conditions, i.e. where a bit is worn out and requires replacement, the bit is tightly gripped and the chuck is unscrewed from the wear sleeve, often with great difficulty, and the bit is then removed from the chuck. In the situation where a bit has broken there may not be a sufficient amount of the bit exposed for gripping so that the chuck can be unscrewed. In this situation a metal bar may be welded to a remaining portion of the bit to provide a sufficient amount of grip to unscrew the chuck. Either operation requires an undesirable amount of time.
Where cluster drills are being used, the bit changing operation requires even more time. The drill must first be removed from the cluster and then the bit is removed from the drill.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.